1. Field
Some example embodiments relate to stamp structures and/or transfer methods using the same.
2. Description of the Related Art
An interest in transfer technology using a polydimethylsiloxane (PDMS) stamp has recently increased. This technology involves fabricating a single crystalline silicon or Group III-V compound semiconductor microribbon which may be manufactured only on a specific substrate, desorbing the single crystalline silicon or Group III-V compound semiconductor microribbon using a PDMS stamp, and transferring the desorbed single crystalline silicon or Group III-V compound semiconductor microribbon to a target substrate. Such technology allows highly functional ribbons requiring particular process conditions (e.g., relatively high temperature, relatively high pressure, an H2 atmosphere, etc.) as well as a specific substrate (e.g., a silicon-on-insulator (SOI) substrate or a GaAs substrate) to be transferred to various substrates, thus enabling manufacturing of various devices.
An adhesion layer such as UV curable polyurethane has been used to transfer single crystalline ribbons adsorbed on a PDMS stamp to a target substrate, but the adhesive material may frequently cause a process limitation. To this end, research into technology for transferring the PDMS stamp without the adhesion layer has been conducted.
Typical methods for transferring a single crystalline ribbon without the adhesion layer include a method that uses viscoelastic properties of the PDMS stamp. In this method, the ribbon may be transferred to a target substrate by promptly desorbing a single crystalline ribbon from a donor substrate to increase a bonding force between the single crystalline ribbon and the PDMS stamp in the case of desorption, and by slowly desorbing the single crystalline ribbon from the donor substrate to decrease the bonding force between the single crystalline ribbon and the PDMS stamp in the case of transferring. In order to control an adhesive force between the single crystalline ribbon and the PDMS stamp more effectively using this technology, a method of controlling adhesive force by reversibly changing a structure of the PDMS stamp has been developed, and a laser driven transfer printing (LDTP) method of transferring the ribbon by irradiating a pulsed laser to an interface between the single crystalline ribbon and the PDMS stamp, thereby causing a thermal expansion difference therebetween, has also been developed.
However, in the method of transferring without an adhesive layer by using a desorption rate and shape control method of a PDMS stamp, since it is difficult to control the uniform desorption rate and the shape over an entire area of a substrate as the substrate and an apparatus are enlarged, it is difficult to manufacture the substrate in a larger scale, and there is a higher possibility of alignment accuracy being reduced during transferring, according to the change in shape of the PDMS stamp. Additionally, since the LDTP method also uses thermal expansion of PDMS, the alignment accuracy may be further reduced during transferring.